feat(moderation): add manual content review system with three-tier AI moderation

Add admin comment moderation endpoints (single and batch) and introduce a three-tier moderation system (pass/review/block) for content flagged by AI. Content with unclear violations is now held for manual review instead of being auto-rejected. Deleted the legacy audit_service.go in favor of the unified hook-based moderation system.

internal/service/post_ai_service.go

@@ -9,7 +9,6 @@ import (
 	"go.uber.org/zap"
 )
 
-// PostModerationRejectedError 帖子审核拒绝错误
 type PostModerationRejectedError struct {
 	Reason string
 }
@@ -21,7 +20,6 @@ func (e *PostModerationRejectedError) Error() string {
 	return "post rejected by moderation: " + e.Reason
 }
 
-// UserMessage 返回给前端的用户可读文案
 func (e *PostModerationRejectedError) UserMessage() string {
 	if strings.TrimSpace(e.Reason) == "" {
 		return "内容未通过审核，请修改后重试"
@@ -29,7 +27,28 @@ func (e *PostModerationRejectedError) UserMessage() string {
 	return strings.TrimSpace(e.Reason)
 }
 
-// CommentModerationRejectedError 评论审核拒绝错误
+type PostModerationReviewError struct {
+	Reason string
+}
+
+func (e *PostModerationReviewError) Error() string {
+	if strings.TrimSpace(e.Reason) == "" {
+		return "post needs manual review"
+	}
+	return "post needs manual review: " + e.Reason
+}
+
+func (e *PostModerationReviewError) UserMessage() string {
+	if strings.TrimSpace(e.Reason) == "" {
+		return "内容需要人工复审，请耐心等待"
+	}
+	return strings.TrimSpace(e.Reason)
+}
+
+func (e *PostModerationReviewError) IsReview() bool {
+	return true
+}
+
 type CommentModerationRejectedError struct {
 	Reason string
 }
@@ -41,7 +60,6 @@ func (e *CommentModerationRejectedError) Error() string {
 	return "comment rejected by moderation: " + e.Reason
 }
 
-// UserMessage 返回给前端的用户可读文案
 func (e *CommentModerationRejectedError) UserMessage() string {
 	if strings.TrimSpace(e.Reason) == "" {
 		return "评论未通过审核，请修改后重试"
@@ -49,6 +67,28 @@ func (e *CommentModerationRejectedError) UserMessage() string {
 	return strings.TrimSpace(e.Reason)
 }
 
+type CommentModerationReviewError struct {
+	Reason string
+}
+
+func (e *CommentModerationReviewError) Error() string {
+	if strings.TrimSpace(e.Reason) == "" {
+		return "comment needs manual review"
+	}
+	return "comment needs manual review: " + e.Reason
+}
+
+func (e *CommentModerationReviewError) UserMessage() string {
+	if strings.TrimSpace(e.Reason) == "" {
+		return "评论需要人工复审，请耐心等待"
+	}
+	return strings.TrimSpace(e.Reason)
+}
+
+func (e *CommentModerationReviewError) IsReview() bool {
+	return true
+}
+
 type PostAIService struct {
 	openAIClient openai.Client
 }
@@ -63,13 +103,12 @@ func (s *PostAIService) IsEnabled() bool {
 	return s != nil && s.openAIClient != nil && s.openAIClient.IsEnabled()
 }
 
-// ModeratePost 审核帖子内容，返回 nil 表示通过
 func (s *PostAIService) ModeratePost(ctx context.Context, title, content string, images []string) error {
 	if !s.IsEnabled() {
 		return nil
 	}
 
-	approved, reason, err := s.openAIClient.ModeratePost(ctx, title, content, images)
+	resp, err := s.openAIClient.ModeratePost(ctx, title, content, images)
 	if err != nil {
 		if s.openAIClient.Config().StrictModeration {
 			return err
@@ -79,19 +118,23 @@ func (s *PostAIService) ModeratePost(ctx context.Context, title, content string,
 		)
 		return nil
 	}
-	if !approved {
-		return &PostModerationRejectedError{Reason: reason}
+
+	switch resp.Result {
+	case openai.ModerationResultBlock:
+		return &PostModerationRejectedError{Reason: resp.Reason}
+	case openai.ModerationResultReview:
+		return &PostModerationReviewError{Reason: resp.Reason}
+	default:
+		return nil
 	}
-	return nil
 }
 
-// ModerateComment 审核评论内容，返回 nil 表示通过
 func (s *PostAIService) ModerateComment(ctx context.Context, content string, images []string) error {
 	if !s.IsEnabled() {
 		return nil
 	}
 
-	approved, reason, err := s.openAIClient.ModerateComment(ctx, content, images)
+	resp, err := s.openAIClient.ModerateComment(ctx, content, images)
 	if err != nil {
 		if s.openAIClient.Config().StrictModeration {
 			return err
@@ -101,8 +144,13 @@ func (s *PostAIService) ModerateComment(ctx context.Context, content string, ima
 		)
 		return nil
 	}
-	if !approved {
-		return &CommentModerationRejectedError{Reason: reason}
+
+	switch resp.Result {
+	case openai.ModerationResultBlock:
+		return &CommentModerationRejectedError{Reason: resp.Reason}
+	case openai.ModerationResultReview:
+		return &CommentModerationReviewError{Reason: resp.Reason}
+	default:
+		return nil
 	}
-	return nil
 }